Sustainable Biomass Functional Monomer-Modified Polycarboxylate Superplasticizers Enable the Creation of High-Performance Cement Pastes

Abstract

In this work, a complex and eco-friendly biomass raffinose monomer-modified polycarboxylate superplasticizer (RAF-PCE) was designed and synthesized via the free radical polymerization technique to simultaneously improve paste fluidity and delay fluidity loss in concrete applications. The adsorption, fluidity, and early hydration behaviors of cementitious systems after the introduction of RAF-PCE have been systematically investigated. Experimental results demonstrate that the hydroxy group in raffinose promotes the adsorption of RAF-PCE on the cement particles, thereby elevating the dispersion characteristic of cement paste through electrostatic repulsion, enabling excellent initial fluidity (310 mm). Additionally, its steric hindrance effect has also been identified to play a role in improving paste fluidity and reducing the slump loss of cement slurry. Detailed analyses unveil that RAF-PCE can reduce the concentration of free Ca2+ in the pore solution through complexation with Ca2+, which prevents the early precipitation of hydration products and realizes a delayed effect on cement hydration, ultimately evolving into a homogeneous and compact microstructure for superior compressive tensile strength of the cement mortar. The 28-day compressive strength of cement incorporating RAF-PCE reached 79.2 MPa, representing a 5.5% enhancement over conventional PCE systems. Our work provides novel insights into the promotion of innovative and green development in the concrete industry by utilizing renewable biomass resources for high-performance materials.